Offset anode ignitron



Jan. 12, 1943. D. E. MARSHALL ETAL 2,303,377

OFFSET ANODE IGNITRON Filed oct. 12, 1940 ATTORNEY Patented Jan. 12, 1943 2,308,377 l OFFSET ANODE IGNITRON Donald E. Marshall, Allwood, and William J.

Knochel, Irvington, N. J., assignors to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application October 12, 1940, Serial No. 360,890

(Cl. Z50-27.5)

7 Claims.

Our invention relates to metal casing discharge devices, and especially to such devices known as sealed-off ignitors.

An object of our invention is to provide a metal casing discharge device, that is suitable for either liquid or air cooling.

Another object of our invention is to simplify the manufacture of sealed-off metal discharge devices.

Further objects and advantages of the invention will be apparent from the following description and drawing in which:

Fig. 1 is a cross section through a preferred embodiment of our invention.

Fig. 2 is a view in top elevation of Fig. l.

' Fig. 3 is a view on lines III- III of Fig. l.

Fig. 4 is a modification of the bottom portion of Fig. 1.

Fig. 5 is a View illustrating the application of a shell'or sleeve to the device of Fig. 1.

Heretofore metal casing discharge devices, and especially the type of device known as a sealedoffignitron, have been generally designed for water cooling. It is one of the objects of our vinvention to arrange the casing of such a device to provide a maximum metal surface for cooling purposes with the result that we have a device that can be interchangeably used, either for liquid or air-cooling means.

lIn attaining this maximum casing surface for cooling, we have also accomplished the result that the anode and ignitron electrodes are supported from a single end header, which provides the further result that these electrodes may be veasily and accurately assembled on this header and then the header slipped into the tube and secured in place.

In Fig. 1 we disclose the main casing I0, which may be of cold-rolled steel or other sturdy material with a closed bottom II to form a place to hold the mercury pool I2. This bottom portion may have a depressed place I3 to provide an additional depth for the igniting electrode I4, which electrode is of high resistance material, such as boron carbide. The depressed portion I3 thus accommodates the immersed tip of the electrode without having the additional mercury necessary for providing the depth disclosed throughout the lower surface.

A tubulation I5 may extend through this lower portion and be sealed of at 16 after heat treatment of the device on exhaust. The upper portion of the metal casing I0 is preferably flanged out at Il to accommodate a cup-shaped header I8 supporting the anode and ignitor electrodes.

This header I8 has two eyelets I9 and 20 Welded about openings 2| and 22 therethrough. These eyelets IYQ and 20 are preferably of a nickel-co halt-iron alloy sold under the trade name of Kovar, and these eyelets are sealed into cylinders 23 and 24 of borosilicate glass. The cylinder 23 is in turn sealed to the edge of a cupshaped metal piece 25, also of the nickel-cobaltiron alloy known under the trade name Kovar.

To the inner closed end surface of this cupshaped metal member is welded or brazed a sturdy conductor 26, extending through the enlarged opening 2| to the interior portion of the casing. The lower endk of this conductor 26 is adapted to be connected to a large carbon block 21 substantially filling the upper portion of the casing I0. The attachment of the carbon block tothe conductor 26 may be accomplished by screw threads 28 on the lower end of the conductor 26, and in addition we preferably insert a metal rod 29 in the central upper portion of the carbon anode and bend it over at 30 to the conductor 26, and weld it to the conductor.

The connection of the conductor 26 to the carbon lblock is approximately in the center of the right-hand semi-cylindrical portion, as disclosed in Fig. 3. Normally, the left-hand portion of the carbon cylinder would interfere with the ignitor connection and, accordingly, we make a slot or groove 3| in the left-hand edge of the carbon cylinder. This slot provides a space for a rod 32 from the ignitor electrode I4 to extend upward towards the header I8.

A rod 33 is preferably connected to this rod 32 and extends upward through an opening 34 in a cup-shaped piece 35, which is of cobalt-nickeliron alloy, known under the trade name Kovar, which is sealed into the cylinder of borosilicate glass 24, previously described. The extension 36 of the ignitor structure may be enlarged to form a hollow portion for the reception of the flexible Vconductor 3'! soldered therein. Extension 36 may also be solid so that a flexible external connection can be made thereto.

The cup-shaped member 25 connected to the anode may likewise have an exterior enlarged member 38 welded thereto and this member 38 may have a socket therein for the reception of a flexible conductor 39.

It will be noted that the Various electrode structures can be readily assembled on the header I8, and then this header construction slipped into the main casing I0 and Welded or brazed thereto. The prior assemblage of the various elements on this header insures their accurate position within the metal casing. If desired, the bottom portion of the container may be assembled by having an inverted cup-shaped header 40 welded or brazed thereto, as disclosed in Fig. 4.

The particular casing structure is also adapted to receive an enclosing sleeve 4I of copper, illustrated in Fig. 5. This copper sleeve Il may be soldered to the cold-rolled steel and insure good electrical as Well as thermal contact to the more sturdy casing l 0. This copper sleeve could have, if desired, a closed end bottom portion 42, disclosed in Fig. 5, in order to protect the tubulation l5. At the upper end it may have an outwardly extending flange 43 for the convenient attachment of an electrical cathode connection or for the insertion in a cooling medium. If desired, instead of the flange 43, the upper portion of the sleeve may closely follow the contour of the flange Il.

It will be noted that the casing l0 provides an extensive surface adapted to radiate a maximum amount of the heat generated in the casing by the operation of the device, because the electrode connections are all centered in the small header at the top of the casing. This arrangment, accordingly, provides a maximum surface for a cooling medium such as water or air from a fan or radiator.

It is apparent that many modifications may be made in the particular form, number and arrangement of the elements shown and, accordingly, we desire only such limitations to be imposed upon our invention as are necessitated by the spirit and scope of the following claims.

We claim:

1. A discharge device comprising a cylindrical metal casing closed at one end, a mercury pool on said closed end, the other end of said casing being hanged-out in cup formation, a cup-shaped metal header closing said cup-shaped end of said casing and seated therein, two openings in said header, an anode having a diameter greater than half the diameter of said casing, a conductor connected to one semi-cylindrical portion of said anode under one of said openings and passing through said opening, insulation between said conductor and said opening, a slot in said anode below said other opening, a conductor extending through said slot, an igniting electrode of high resistance material on the inner end of said conductor partially immersed in the mercury, the other end of said conductor extending through said other opening and insulation between said conductor and said header.

2. A discharge device having a cup-shaped casing of steel, a header closing said casing, connectors sealed through said header, electrodes on the ends of said connectors and a sleeve of copper soldered to and in physical contact with the exterior surface of said casing of steel substantially the full length thereof below the header.

3. Anode structure for a discharge device comprising a mass of carbon having at least one flat side, a connection inserted in said mass through an oir-center opening in said ilat side, a rod inserted in the center of said side and secured to said connection.

4. Anode structure for a discharge device comprising a cylinder of carbon, a connection inserted in said cylinder through an off-center opening in one of the iiat circular sides, a rod inserted in the center of said circular side and secured to said connection.

5. Anode structure for a discharge device comprising a cylinder of carbon, a connection inserted in said cylinder through an ofi-center opening in one of the flat circular sides, a rod inserted in the center of said circular side and secured to said connection, and a slot in the cylindrical surface farthest from said off-center opening.

6. A discharge device comprising a metal cupshaped casing, a mercury pool cathode in the bottom of said casing, said bottom of the casing having a depression oiset from the center thereof and affording greater depth of mercury thereat, an `anode lling a, large portion of the upper portion of said casing, an off-center connection to the upper portion of the anode, an auxiliary electrode at the surface of said mercury pool, said auxiliary electrode being offset from the center of the casing and having its lower end in said offset depression, a connection from said auxiliary electrode passing through a cut-away portion of said anode, a header on the top of said cupshaped casing and insulation sealing said anode and auxiliary electrode connections in openings in said header.

7 A discharge device comprising a metal casing with a flanged-out cup formation at its upper end, a cup-shaped metal header seated in said flanged-out cup formation of the casing, necklike metal eyelets secured to said header projecting in a direction outward longitudinally of the casing and parallel to each other and each having a diameter less than the radius of the casing, an inverted cup-shaped metal piece for each said neck-like eyelet of substantially the same diameter thereas and above the end thereof, and an insulating cylinder interposed between each said eyelet and its inverted cupshaped metal piece of substantially the diameter of the respective eyelet and cup-shaped piece and sealed with respect thereto, conductors mounted upon said inverted cup-shaped metal pieces axially thereof extending one through each and projecting each downwardly through the insulating cylinder and eyelet into the casing, and electrodes carried by each said conductor within the casing.

DONALD E. MARSHALL. WILLIAM J. KNOCHEL. 

